As promised, I have completed the ICND2/CCNA level lab project for those of you studying toward that certification. I have done my best to map this to the various 200-101 requirements and again based it on Packet Tracer. You may download it at ICND2 Lab Project Exercises 7-2014. In addition, to simplify the process of getting the startup file, you may download that file here.

Some months ago, I decided to create another lab guide based on the CCENT. While this draws more from my previous lessons on the ICND1, the content is still relevant. I elected to use Packet Tracer to create this, knowing that it supports most of the lab requirements and is portable. I will begin working a CCNA level lab guide shortly.

To those first getting into the “wonderful world of networking,” things can sound mysterious and downright confusing, and in many ways like learning a foreign language. Often language instructors use a “sound alike” method to help learners associate the new word with those they already know. For example, the word akou in Greek means “to hear”; words in English derived from that are those like “acoustic.” Using the familiar to teach the unfamiliar is a helpful way to assist understanding on the part of the learner.

In this post, I want to use this same method to explain the meaning and hierarchy of IP (IPv4) addressing. My hope is that this helps to clarify the concepts somewhat.

When I first saw an IPv4 address, it made absolutely no sense to me, and I try to keep that in mind as I teach concepts that are new to students. As I reflected on this recently, I thought of a way to reduce to plain concepts, as I will present in this post.

The first thing to understand when you see the string of numbers like those shown above, forget the weird notation and just concentrate on the description…an address! When you mail a letter, you have to specify who it’s for and where it needs to go for the recipient for get it, including cities, states/provinces, postal code, etc. Each part of an IPv4 address has the same types of functions.

The first number, 192, specifies a large group of other addresses, like a zip code or a designation for a city. Note here that it collectively refers to all of these homes at once, as a more general identifier.

Any region, city, or town contains smaller units, which could be groups of homes, in this case, all the homes off of a major road within the city. Here we are using the identifier of 168th Avenue, which is within city 192, giving the area the identifier 192.168.

Finally, we get down to a single neighborhood, located off 168th Avenue, which is also located within city 192. This smaller neighborhood contains all the homes off 101st street, and each house has a street number. The identifier for all of these homes would be 192.168.101.0 (0 in this example just means everything within that neighborhood). The complete address for the home all the way to the right would be 192.168.101.150.

One final thing to note is the concept of the default gateway for a network, which would how all traffic destined outside the neighborhood would go. Since the street is a dead end, the only way out is through the guarded gate,which has the address of 100 (192.168.101.100).

As is the case with anything new and unfamiliar, IPv6 can appear strange, hard to understand, and downright confusing! Often, when learning new content, it helps to compare or even anchor the concepts in something more familiar, as depicted above with the photo of two very different dog breeds. In this example, the contrast is plainly visible; one dog towers over the other, and each have variances in coloring, build, and a dozen or more differences. Even so, both are still dogs, with four legs, a keen sense of smell, ability to learn, and even “man’s best friends.” Even though the differences may appear vast, the similarities are much greater in number. This is precisely the case with IPv6, as it represents a different “breed” or “species” of the Internet Protocol, but with many similarities to its predecessor; think of IPv6 as IP 2.0! One are, which we shall consider now, has to do with addressing types in this new version of the Internet Protocol, namely the types of multicast, anycast, and unicast.

Multicast

In IPv4, multicast addressing was encompassed the Class D space of 224.0.0.0 – 239.255.255.255, and used to address multiple hosts. Broadcast addressing, on the other hand, sent messages to every host on the LAN/VLAN segment in question. As mentioned previously, IPv6 eliminated the use of broadcasts, in favor of multicast functionality. Formatting of multicast addresses in IPv6 requires use of the prefix FF, and the basic mechanics are the same as IPv4.

Anycast

To even seasoned engineers, the concept of anycast addressing can sound confusing and rather contradictory, as it calls for the use of identical addressing on multiple devices. To be frank, I myself struggled with this for years before inadvertently stumbling on an explanation that made the idea much clearer in my mind. Anycast is often used on servers to provide resiliency, such as is the case on DNS servers, and often used by service providers for this every purpose. IP routing directs the requesting device to the nearest server using standard routing metrics which can provide load-sharing as well as failover capabilities. To better understand this, think of the process by which an end-user utilizes a SmartPhone or GPS device. The user enters the name of a familiar grocery store, for example (Safeway, Albertsons, etc.), and may get half a dozen responses, along with the distance to reach each one. ALL the stores have the same name, but each is a different distance from the standpoint of the user, who normally selects the CLOSEST. This is precisely how anycast addressing works.

Unicast

Unicast addressing in IPv6 operates the same way as it does in IPv4, but has a number of subtypes, which will be addressed in the next article.

As I wrapped up another class on ICND2, I created a fairly comprehensive lab that covers many of the major topics on the ICND2 exam. Take a look, I certainly hope it helps with the preparation process for the CCNA!

I recent have been leading another set of students through the ICND1 & 2, and created a series of labs designed to reinforce the learning concepts in the course. These have been created in Packet Tracer, which is intended for students in the Cisco Networking Academy program, though they can be easily created in other simulators and on actual equipment. I am posting the lab guides for your use, I am unable to post the configuration files. If you have any questions, let me know.

I grew up during the 1970’s, a period well before the advent of many of the technologies that we virtually take for granted today. Back then, you often shared a phone line with another neighbor (called a party lin), there were no answering machines, and personal computers simply didn’t exist. In addition, if you missed a movie at the theater or on television, you were simply out of luck altogether. Today you carry your telephone with you, can stream movies on that same device, and carry on real-time video conversations with someone literally on the other side of the planet! The point of this “flashback” is simply to highlight that time and technology marches on, leaving some things in the dust of obsolescence.

This is precisely the situation in which the beloved Internet Protocol (referred hereafter as IPv4) finds itself in today. Granted, it has not passed off the technology world stage (nor will it anytime soon), but is displaying signs of its definitive sunset years. In a lot of ways, IPv4 became a victim of its own success, after beating out other routable protocols such as IPX and Appletalk, among others. Globally routable address space was becoming rapidly depleted, Internet routing tables were ridiculously large, and yet the proliferation of devices continued unabated. As a result, in the 1990’s, short-term solutions such as Classless Interdomain Routing (CIDR), Private Addressing, and Network Address Translation (NAT), were implemented, but the long-term solution was a newer version altogether.

Enter IP Version 6, typically just called IPv6, designed from the ground up to address all of the shortcomings of its predecessor, the venerable IPv4 protocol. You may immediately wonder why the version number jumps from version 4 to 6, instead of simply 5, and the answer is simply that IPv5 was experimental and never actually released, similar to versions 1-3. While not exhaustive, here are some major improvements brought to you exclusively by IPv6:

Address Assignment Features: Hosts can calculate their own addresses, as well as take advantage of new DHCP features

No More NAT: Due to the vast availability of addresses, having to implement private addressing and Network Address Translation is simply no longer necessary

Elimination of Broadcasts: Broadcasts are a necessary evil in IPv4, but no longer used in IPv6, instead using multicast-driven protocol mechanisms

Integrated Security: When the now-familiar IPsec protocol first came out, protocol analyzers would label the packets as IPv6, partly because the mechanism was originally designed for it, and is native in IPv6.

As you can see, there are many new mechanisms and features in this up and coming version of the Internet Protocol, which is certainly and inevitably in our collective future.